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Hybrid phononic crystals for broad-band frequency noise control by sound blocking and localization
Sungmin Yoo1, Yoon Jae Kim, Yoon Young Kim
1School of Mechanical and Aerospace Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744, Republic of Korea. novalisg@snu.ac.kr
Abstract:
A bandgap cannot be enlarged sufficiently enough to suppress a broad-band noise only with a single type of finite-length phononic crystals. Here, a hybrid phononic crystal consisting of a bi-prism and an inverted bi-prism is proposed for noise control in a broad band; a stop band is formed in a central frequency range while positive-positive and positive-negative refractions occur in lower and higher frequency ranges to concentrate acoustic energy in a central localized zone. Thereby, the remaining zone becomes little affected by the noise. Analysis and numerical simulations are given for the justification of the proposed configuration.
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